HT4100 4.1, 4.5, 4.9 Discussion, car is dieing at idle. P048 current trouble code. in Cadillac Engine Technical Discussion; Gee this threads getting old. I still don't see any mention of a vacuum reading even after it's been to ...

Re: car is dieing at idle. P048 current trouble code.

Gee this threads getting old. I still don't see any mention of a vacuum reading even after it's been to a shop. Does the car have good power while it's running? I was thinking if it had low vacuum it might be a clogged catalytic. If the car still has good power it may not be. If the engine pulls 18 in of vacuum then everything is working normally. Did anyone try to adjust or replace the ISC? That's what actually controls the idle. The EGR code is puzzling since it seems to be working and it has now been replaced too. I have had a clogged cat cause an EGR code in the past.